\begin{table}[htbp]\centering
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\caption{Effect of MPD under different supply-side conditions\label{tab\_tr: supply-side}}
\begin{tabular}{l*{6}{c}}
\toprule
                    &\multicolumn{1}{c}{(1)}&\multicolumn{1}{c}{(2)}&\multicolumn{1}{c}{(3)}&\multicolumn{1}{c}{(4)}&\multicolumn{1}{c}{(5)}&\multicolumn{1}{c}{(6)}\\
\midrule
treated             &      -0.022\sym{***}&      -0.020\sym{***}&      -0.024\sym{***}&      -0.022\sym{***}&      -0.023\sym{***}&      -0.021\sym{***}\\
                    &    (0.0003)         &    (0.0004)         &    (0.0002)         &    (0.0002)         &    (0.0002)         &    (0.0002)         \\
\addlinespace
tr\_comp\_1           &      -0.000         &      -0.000         &                     &                     &                     &                     \\
                    &    (0.0004)         &    (0.0005)         &                     &                     &                     &                     \\
\addlinespace
tr\_comp\_2           &      -0.001\sym{**} &      -0.001\sym{**} &                     &                     &                     &                     \\
                    &    (0.0004)         &    (0.0005)         &                     &                     &                     &                     \\
\addlinespace
tr\_comp\_3           &      -0.002\sym{***}&      -0.002\sym{***}&                     &                     &                     &                     \\
                    &    (0.0004)         &    (0.0005)         &                     &                     &                     &                     \\
\addlinespace
tr\_comp\_4           &      -0.001\sym{***}&      -0.001\sym{**} &                     &                     &                     &                     \\
                    &    (0.0004)         &    (0.0005)         &                     &                     &                     &                     \\
\addlinespace
tr\_comp\_5more       &      -0.003\sym{***}&      -0.002\sym{***}&                     &                     &                     &                     \\
                    &    (0.0003)         &    (0.0004)         &                     &                     &                     &                     \\
\addlinespace
tr\_integrated       &                     &                     &       0.000         &       0.000         &                     &                     \\
                    &                     &                     &    (0.0002)         &    (0.0002)         &                     &                     \\
\addlinespace
tr\_oligopoly        &                     &                     &                     &                     &      -0.001\sym{***}&      -0.002\sym{***}\\
                    &                     &                     &                     &                     &    (0.0002)         &    (0.0002)         \\
\midrule
Observations        &     6256789         &     7141675         &     6256789         &     7141675         &     6256789         &     7141675         \\
Adjusted \(R^{2}\)  &       0.811         &       0.824         &       0.811         &       0.824         &       0.811         &       0.824         \\
\bottomrule
\multicolumn{7}{l}{\footnotesize Standard errors in parentheses}\\
\multicolumn{7}{l}{\footnotesize SEs clustered at the fuel station level.}\\
\multicolumn{7}{l}{\footnotesize \sym{*} \(p<0.10\), \sym{**} \(p<0.05\), \sym{***} \(p<0.01\)}\\
\end{tabular}
\end{table}
